Biodegradable waste remediation method and system

ABSTRACT

Contaminant treatment methods and systems are described. Methods utilize biodegradable, non-toxic materials that can carry one or more functionalities useful for the remediation of fluids such as liquid or gaseous waste streams, chemical spills, etc. The carrier materials carry one or more functional groups that can target particular contaminants of a fluid for removal and/or modification to a more benign form. Targeted contaminants can include components of gaseous and/or liquids such as, and without limitation, gaseous discharges including VOCs and potentially hazardous contaminants such as organophosphorous compounds.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims filing benefit of United StatesProvisional Patent Application Ser. No. 62/110,876 having a filing dateof Feb. 2, 2015, which is incorporated herein by reference for allpurposes.

BACKGROUND

The safe and effective remediation of waste or other environmentalcontaminants continues to provide challenges to industry growth anddevelopment as well as to environmental safety. For example, volatileorganic compounds (VOCs) emitted from processing plant waste in avariety of industries often produce noxious odors and can presentdeleterious health effects. These odors alone can prevent theconstruction of new facilities, even when the VOCs present little or nohealth or environmental hazards. Unfortunately, processes that producemalodorous by-products generally produce multiple different VOCs, andmethods for eliminating a plurality of such compounds can be quitecomplicated and expensive.

There are many industries that produce VOCs as by-products, someexamples include, but are not limited to: rendering, refiningoperations, landfills, waste-water treatment plants, paper mills,livestock farms, chemical plants, etc. Additionally, certain industrialfood operations such as industrial baking operations, coffee roasters,chocolate factories, chili sauce factories, etc. can present persistentnuisance odor problems for nearby residents.

As one example, rendering is a field that is strongly associated withthe production of malodorous by-products, and is inextricably linked tothe success and efficiency of the broader agricultural enterprise in theUnited States. The total output of materials from slaughterhouseoperations not directly consumed by humans exceeds 54 billion pounds peryear. Rendering processes cook down these by-products to drive offmoisture, separate the animal fats, and concentrating the protein-richmaterial into dry meals as well as other useful products. Renderingallows for the efficient removal, decontamination, and repurposing ofthe very large by-product stream from livestock and slaughterhouseoperations. Alternative disposal strategies for slaughterhouse offal,including landfilling or incineration, pose serious environmentalconcerns in terms of the potential for water and soil contamination. Inaddition, these alternative methods don't remove and can even exacerbatethe problem of the venting of noxious emissions.

The positive environmental impact of rendering in terms of reducing theamount of landfill and biological waste from the aforementionedoperations is often overshadowed by negative perceptions of theenvironmental impact of rendering in terms of wastewater and odoremissions. Indeed, untreated emissions from rendering operations can bedetected up to 20 miles away from the source, and concerns over odoremissions often play a large role in community resistance to siteselection for new rendering operations. Significant efforts and capitalhave been invested into controlling odor emissions that result from thisas well as other industries, but room for improvement remains.

The handling of malodorous industrial by-products is not the onlyenterprise that could benefit from improved waste-treatment systems andmethods. Organophosphorous (V) compounds represent a large class ofcompounds that are employed in a range of uses including chemicalwarfare agents, pesticides, and flame retardants. If not properlyhandled and disposed of, these materials can be introduced into theenvironment as dangerous and even deadly toxins. Organophosphorouschemical warfare agents are deadly toxins that exhibit lethality by theinhibition of acetylcholine esterase resulting in continual nervestimulation. Organophosphorous pesticides and herbicides such aschloropyrifos, diazinon, and malathion enjoy broad use in agricultureand residential applications. Despite their reduced toxicity compared tochemical warfare agents, they still exhibit central nervous systemtoxicity and have been implicated in the advent of liver dyslipidemia inrodent models. Organophosphorous flame retardants (OPFRs) like triphenylphosphate (TPP), cresyldiphenylphosphate (CDPP), and 2-ethylhexyldiphenylphosphate (EHDP) are broadly applied in a variety of settingsincluding furniture, textiles, vehicle interiors, electronics andcomputers, plastics, and building materials. OPFRs have been detected inmany environmental settings including indoor air, dust, drinking water,and soil sediments and often find their way into the waste stream.

While methods and materials have been developed to treat and/or removecontaminants such as VOCs and potentially toxic materials from wastestreams, these methods are often elaborate and expensive, and themethods and materials used often present additional issues. Forinstance, known waste treatment materials generally lack specificity forcontaminants, and as such a large volume of treatment material can berequired to ensure removal of the targeted contaminants. This can leadto additional disposal issues, as the secondary materials used to targetthe primary contaminants must also be removed, and a large volume ofadditional waste can be generated by the waste treatment process itself.Moreover, known waste treatment materials can present their own toxicityissues and are not biodegradable, adding additional problems to thewaste treatment process.

What are needed in the art are materials, methods and systems for theremediation of environmental contaminants. For instance, biodegradableand non-toxic materials that can be utilized for the targeted chemicalmodification or sequestration of malodorous and/or environmentallyharmful compounds would be of benefit.

SUMMARY

According to one embodiment, disclosed is a method for remediating afluid. For instance, a method can include contacting a fluid (e.g., aliquid or a gaseous fluid) with a biodegradable carrier material. Thefluid includes a contaminant that is targeted for removal and/ormodification according to the remediation process such as a malodorousVOC or a toxic compound. The biodegradable carrier material includes abiodegradable polymer and also includes a functional group. Thefunctional group has been predetermined for interaction with thetargeted contaminant. The interaction between the functional group andthe targeted contaminant can be but not limited to, bonding between thetargeted contaminant and the functional group by which the targetedcontaminant can be sequestered and removed from the fluid or degraded ordeactivated. In one embodiment, the interaction between the functionalgroup and the target contaminant can be but not limited to formation ofa covalent bond, formation of an ionic bond, electrostatic interaction,and or hydrophilic/hydrophobic interaction. In one embodiment, theinteraction can be but not limited to low affinity but high avidity orhigh affinity but low avidity. In one embodiment the interactions can bebut not limited to monofunctional or multifunctional. In one embodiment,the interaction can include reaction of the targeted contaminant withthe functional group by which the contaminant can be modified and thusrendered safe for disposal.

Also disclosed are systems containing the biodegradable carrier materialthat can be used in carrying out the disclosed methods. In oneembodiment, a system can include a fluid flow path and the biodegradablecarrier material located in the fluid flow path such that a fluidtraveling in the path will contact the biodegradable carrier material.For example, the carrier material can be in the form of particles orfibers that can be a component of a fluidized bed, a filter apparatus,protective clothing, or some other device that can provide for contactbetween the carrier material and the fluid carried in the flow path. Inone embodiment, the biodegradable carrier material can be inside,outside, and/or between membranes in a system.

BRIEF DESCRIPTION OF THE FIGURES

The presently disclosed subject matter may be better understood withreference to the Figures, of which:

FIG. 1 schematically illustrates a general strategy for a method asdisclosed herein.

FIG. 2 schematically illustrates a general strategy for a method asdisclosed herein.

FIG. 3 presents exemplary targeted materials from a rendering processfor a method as disclosed herein.

FIG. 4 illustrates a carrier material including an amine functionalgroup.

FIG. 5A illustrates the reaction of an amine functionalized carriermaterial with an aldehyde contaminant.

FIG. 5B illustrates the reaction of an amine functionalized carriermaterial with a carboxylic acid contaminant.

FIG. 6 illustrates a carrier material including an ammoniumperoxysulfate functional group.

FIG. 7 illustrates the oxidation of a sulfurous contaminant to a lessnoxious compound according to one embodiment of the disclosed methods.

FIG. 8 illustrates one method for forming an oxime functionalizedcarrier material.

FIG. 9 illustrates the oxidation of an organophosphorous contaminantaccording to one embodiment of the disclosed methods.

FIG. 10 illustrates one embodiment of a bifunctional carrier material.

FIG. 11 illustrates a packed bed treatment system.

FIG. 12 illustrates a filter cartridge as may be incorporated in atreatment system.

FIG. 13 illustrates a testing system utilized to examine methods andsystems as described herein.

FIG. 14 graphically compares the ability of three differentfunctionalized carrier materials to target a VOC contaminant in asample.

DETAILED DESCRIPTION

Reference will now be made in detail to various embodiments of thedisclosed subject matter, one or more examples of which are set forthbelow. Each embodiment is provided by way of explanation of the subjectmatter, not limitation thereof. In fact, it will be apparent to thoseskilled in the art that various modifications and variations may be madeto the disclosed subject matter without departing from the scope orspirit of the disclosure. For instance, features illustrated ordescribed as part of one embodiment may be used with another embodimentto yield a still further embodiment.

In general, the present disclosure is directed to the utilization ofbiodegradable, non-toxic materials that can carry one or morefunctionalities useful for the remediation of fluids such as liquid orgaseous waste streams. More specifically, the carrier materials cancarry one or more functional groups that can target particularcomponents of a fluid for removal and/or modification to a more benignform. Targeted contaminants can include but are not limited tocomponents of gaseous and/or liquid fluids such as, and withoutlimitation, gaseous discharges including VOCs and potentially hazardouscontaminants such as organophosphorous compounds.

General strategies of methods for remediating a fluid are illustrated inFIG. 1 and FIG. 2. Briefly, in the method of FIG. 1, a carrier material10 is surface decorated with reactive functional groups (FGs). Thefunctional groups FG react with and bind to target contaminants 12contained within a fluid such as a waste stream 8. By considering thechemical reactivity of the target contaminant 12, the surface FGs of thecarrier material 10 can be tuned to bind the target contaminantsaccording to any suitable binding mechanism (e.g., a covalent ornon-covalent binding mechanism, charge/charge interaction, etc.) andsequester the target contaminant 12. The waste stream 8 can thus becleared of the target contaminant.

Beneficially, the carrier material 10 can be non-toxic andbiodegradable, allowing for spent materials 16 to deteriorate aftersequestration and removal of the target contaminant 12 from the wastestream 8. The target contaminant 12 can be concentrated as compared tothe concentration of the target contaminant 12 in the waste stream 8 anddisposed of or further processed as desired. For instance, in oneembodiment the targeted contaminant 12 can require additional processingprior to final disposal. Due to the biodegradability of the carriermaterial 10, this further processing need not include a step for removalof the targeted material 12 from the carrier material 10 or anyadditional processing of the carrier material 10, as the carriermaterial is biodegradable and non-toxic and thus will present no seriousdisposal issues. Alternatively, should the targeted material 12 retain auseful value, the targeted material 12 can be recovered from the spentmaterial 16 following degradation of the carrier material. Throughsequestration and removal of the targeted material 12 by use of thenon-toxic and biodegradable carrier material 10, the final volume of thespent material 16 following biodegradation can be limited to only theremaining breakdown products of the carrier material 10 (e.g., water andcarbon dioxide) and the concentrated targeted material 12, which cansimplify the recovery, reprocessing, and/or disposal of the targetedmaterial 12.

In an alternative embodiment illustrated in FIG. 2, the functionalgroups FG of the carrier material 10 can be designed to react with thetargeted material 22 of the fluid, e.g., a waste stream 28. Upon thereaction, the targeted material 28 can be modified to a more acceptablematerial 27. For example, the reaction can oxidize, reduce, or otherwisealter the targeted material 22 to form a non-toxic compound 27 that canbe disposed of or released without additional processing. The spentmaterial 26 can include only the biodegradation products of the carriermaterial 10 and the reaction products (if any) of the functional groupsFG, which can be disposed of or reprocessed as desired.

The carrier material can include a biodegradable polymer encompassinghomopolymers and copolymers and including, without limitation linearpolymers, branched polymers, monovalent polymers, multivalent polymers,random copolymers, block copolymers, grafted polymers, crosslinkedpolymers, etc., and can be in any suitable form for contact with thetargeted material. For instance, while illustrated in FIG. 1 and FIG. 2as a spherical particulate, it should be understood that the carriermaterial can be in any suitable form, shape, or size. By way of exampleand without limitation, the carrier material can be in the form ofnano-sized and/or micro-sized particles. Particle shapes can be, e.g.,spherical, cylindrical, polymorphic, star-shaped, platelets, ovoid,square, amorphous, or any other shape or mixtures of shapes. Carriermaterials can alternatively be in the form of sheets or films, fibers,or any other convenient form.

Polymers as may be utilized in forming the carrier materials canencompass any natural or synthetic non-toxic and biodegradable polymerthat can function in the waste treatment environment expected in theprocess. For instance, the biodegradable polymer can have a glasstransition temperature greater than the expected temperature of thefluid waste stream. As utilized herein, the term “biodegradable”generally refers to a material that will degrade over time to formnon-toxic break-down products by the action of enzymes, by hydrolyticaction and/or by other mechanisms of biological materials or systems. Asutilized herein, the term “non-toxic” generally refers to a materialthat is not injurious to health of plants, organisms, animals, and/orhumans that is held in sustained contact with the material.

The polymeric carrier materials can include homopolymers and/orcopolymers and can encompass multi-component materials. For example,block copolymers in which the blocks vary according to somecharacteristic (e.g., hydrophobic/hydrophilic, charge characteristics,etc.) can be utilized that can self-organize to present a higherproportion of one of the components on the surface of the carriermaterial for contact with a waste stream and the targeted contaminant(s)therein. For example, a copolymer including a biodegradable hydrophobiccomponent (e.g., poly(lactic acid)), and a hydrophilic component such aspolyethylene glycol can be utilized that can self-organize to presentthe polyethylene glycol at the surface of the carrier material, whichcan then be functionalized as described further herein.

Multi-component materials can include two or more different materialsthat are combined together to form a single structure as an intimateblend or in separate areas of the structure (e.g., a core/shell particleor fiber). The different materials can be organized so as to present asingle material at a contacting surface of the carrier material or so asto present different materials in different zones of the carriermaterial. For example, a multi-component fiber in the form of acore/shell fiber can present one material at the fiber surface forcontact with the waste stream and can include a second material as aninner core of the fiber. In an alternative arrangement, a first materialcan form a first outer surface of the formation and a second materialcan form a second outer surface of the formation, such that bothmaterials may contact the waste stream and the targeted contaminant(s)therein, and can do so in different zones of the total contact area.

Exemplary non-toxic and biodegradable polymers for use in forming thecarrier material can include, without limitation, collagen, alginatesand alginate derivatives, polysaccharides, polyethylene glycol (PEG),poly(glycolic acid) (PGA), poly(lactic acid) (PLA) including D-lactide,D,L-lactide, or L-lactide, poly(lactide-co-glycolide) (PLGA), gelatin,agarose, natural and synthetic polysaccharides, polyamino acids such aspolypeptides including poly(lysine), polyesters such aspolyhydroxybutyrate and poly-ε-caprolactone, polyanhydrides,polyphosphazines, poly(vinyl alcohol) (PVA), PVA-ε-PLGA, poly(alkyleneoxides) such as poly(ethylene oxides) (PEO), poly(allylamines)(PAM),acrylam ides such as poly(acrylic acid) (PAA) andpoly(acrylonitrile-acrylic acid), modified styrene polymers such aspoly(4-aminomethylstyrene), pluronic polyols (e.g., PEO-PPO-PEO),polyoxamers, poly(uronic acids), poly(vinylpyrrolidone), poly(α-hydroxyacids) and conjugates thereof, polyorthoesters, polyaspirins,polyphosphagenes, starch including pre-gelatinized starch, hyaluronicacid, chitosans, albumin, fibrin, vitamin E analogs such as α-tocopherylacetate, d-α-tocopheryl succinate, caprolactone, dextrans,vinylpyrrolidone, methacrylates, poly(N-isopropylacrylamide), PEGT-PBTcopolymers, PEO-PPO-PAA copolymers, PLGA-PEO-PLGA copolymers, PEG-PLGcopolymers, PLA-PLGA copolymers, poloxamers, PEG-PLGA-PEG triblockcopolymers, SAIB (sucrose acetate isobutyrate), PLA-PEG copolymers,hyaluronic acid, or combinations thereof.

The polymeric materials can include other additives as are known in theart in addition to the non-toxic, biodegradable polymers according tostandard practice and including, without limitation, processing aids,nucleation agents, colorants, lubricants, strength additives (e.g.,fibrous additives), thermal protectant materials, and so forth.Additives can generally be combined with the polymers in standardamounts and can be non-toxic such that the final polymeric carriermaterial and degradation products of the carrier material are alsonon-toxic.

The polymers and/or other additives used in the formation of the carriermaterials can be processed as necessary to provide a desired stabilityof the carrier materials both before and after sequestration or reactionwith the targeted contaminant. For instance, when employed in anindustrial setting for capturing VOCs, a robust and stable material thatwill begin to biodegrade only after the carrier material is fully spentand slated for disposal (or regeneration) can be preferred. Conversely,in an embodiment in which the carrier material is to be employed in arapid-dispense emergency situation, (e.g. to counteract theenvironmental release of a chemical warfare agent or pesticide) acarrier material that rapidly neutralizes the targeted contaminantthrough reaction and then quickly biodegrades on-site into innocuousby-products may be preferred.

The degradation profile of the carrier materials can be tuned within adesired time frame ranging between, for example, a few minutes toseveral years. In general, the desired degradation profile of thematerial will depend heavily upon its desired end-use, expected pre-useshelf life, post-use processing and disposal of sequestered materials,and the like. Methods for controlling the degradation profile of thecarrier materials can include, for instance, selection of polymerformulation, formation and density of crosslinks in the polymer(s),combination and organization of different materials, and so forth.

The carrier materials can be formed to any desired shape and sizeaccording to standard methods as are known in the art. For instance,carrier materials can be formed as continuous or chopped fibersaccording to melt extrusion methods (e.g., melt spinning, melt blowing,etc.) as are generally known. Sheets or films formed of the carriermaterials can be formed according to solution or melt casting processes,extrusion processes, and so forth.

In one embodiment, the carrier materials can be in the form of nano ormicro-sized particles. Particles of the carrier materials can be formedaccording to standard practice. For instance, an emulsification solventevaporation method or an emulsification solvent diffusion method can beutilized to form micro- or nanoparticles of the carrier material.Briefly, one embodiment of a particle formation process can include afirst step of emulsification in which the biodegradable polymer isdissolved in a solvent (e.g., an organic solvent) and then the emulsionis formed by adding this phase (e.g., an organic phase) to a secondphase (e.g., an aqueous phase) and stirring. Following, the solvent canbe removed from the emulsion by evaporation or dialysis. Finally, thenanoparticles can be obtained after freeze dehydration.

The variability of the carrier materials with regard to both compositionand form provides a route to the development of a system that can bespecifically designed for a particular waste treatment process. Thestability, polymer characteristics, break-down products and physicalform of the carrier material can be altered to best suit the applicationof the materials. This can be of great benefit in designing a wastetreatment process and system that can optimize the capabilities of thecarrier materials and functional groups and efficiently target one ormore contaminants in a waste stream.

The carrier materials carry one or more functional groups that can bepre-determined for a particular application of the materials. Forinstance, and depending upon not only the targeted contaminant(s) of afluid but also on the overall characteristics of the fluid (e.g.,flowing or static, volume, temperature, state, pressure, etc.) and thefinal disposal or recovery of the targeted contaminants, the functionalgroups can be predetermined and applied to the carrier material inaccord with the desired function.

The functional groups carried by the carrier materials can bespecifically targeted to a single material of a fluid or can be targetedto a plurality of different contaminants in a fluid. For instance,rendering emissions are a well-characterized yet complex mixture of avariety of chemicals, with about 110 distinct volatiles that have beendetected and identified, and with 26 of those confirmed to contribute tothe unsavory odors of cooking processes. Many of these volatiles arehighly flammable, corrosive, carcinogenic, and/or toxic to both humansand animals and as such present potential targeted materials for a wastetreatment system as disclosed herein.

FIG. 3 presents a summary of the 26 offending odorants found inrendering emissions as well as a general depiction of their commonfunctional group. The list contains ten aliphatic aldehydes ranging fromthree to ten carbons in length. Carboxylic acids comprise the secondmost populous group, containing examples ranging from two to six carbonsin length. Sulfur containing functional groups (including thiols,sulfides, disulfides, and trisulfides) comprise the third largest groupof offending odorants. Additionally, a single alcohol and a single aminehave been identified. Most of these volatile organics result from thethermal breakdown of protein and fats during the cooking process. Thiswell-defined, yet still complex mixture of a variety of distinctchemical entities presenting a number of distinct chemical functionalgroups is one example of contaminants in a waste stream that can betreated according to the disclosed methods and system for theremediation of VOC environmental contaminants.

Of course, the above is just one example of mixtures of contaminantsthat can be treated by use of the disclosed methods and systems.Contaminants that can be targeted by the methods can have any structureand be by-products or waste from any industry or environment. Forexample, contaminants can be simply malodorous, can be malodourous aswell as toxic, can be toxic but not malodorous, or can be undesirabledue to some other characteristic or combination of characteristics. Forinstance, small, highly volatile compounds such as propanal (analdehyde) and/or propionic acid (a carboxylic acid) can be targeted ascan branched compounds such as the aldehyde 2-methylbutanal and/or thecarboxylic acid isovaleric acid. Contaminants can include, for exampleand without limitation, halogenated contaminants (e.g., dichloroethane),acids (e.g., acetic acid), organic solvents (e.g., acetone),agricultural contaminants (e.g., ammonia), aromatic contaminants (e.g.,benzene), etc. Carrier materials including functional groups can beengineered to target chemical entities of interest includingpharmaceuticals, components of personal care products, perchlorates,endocrine-disrupting compounds, and so forth. In one embodiment,contaminants encountered in day to day living can be targeted. Forinstance, malodourous or otherwise undesirable contaminants in home orwork environments such as cigarette smoke contaminants, kitchenmalodors, and the like can be targeted.

Multiple contaminants having the same or different targeted functionalgroups that are present in a single fluid can be sequestered and/ormodified according to disclosed processes either sequentially orsimultaneously. For instance methods and systems can be designed totarget a mixture of aldehyde and carboxylic acid VOC contaminants in asingle gaseous waste stream with a single sequestering/modification steptargeting multiple aldehydes (e.g., targeting both hexanal and2-methylbutanal) in a single step, multiple carboxylic acids (e.g.,targeting both hexanoic acid and isovaleric acid) in a single step, orboth aldehydes and carboxylic acids (e.g. hexanal and hexanoic acid) ina single step. In one embodiment, all of the targeted contaminants of awaste stream can be simultaneously removed and/or modified in a singletreatment step.

Beneficially, the carrier materials can be designed to specificallytarget contaminants in a fluid while not being fouled by other materialsthat may also be in the fluid in conjunction with the contaminants. Forinstance, gaseous emission streams can often include materials such ascarbon dioxide in levels acceptable for release (e.g., atmosphericlevels). Disclosed carrier materials can target the desired contaminantsin the presence of other compounds such as carbon dioxide without beingfouled due to interaction of the functional groups of the carriermaterials with the other, non-targeted fluid components.

Of course, disclosed methods and systems are not limited to either themalodorous contaminants of a rendering process emission or to VOCs.Other contaminants in liquid, vapor, or gaseous state can be targetedaccording to disclosed methods. For instance, in one embodiment, a fluidcontaining one or more organophosphorous (OP) compounds including,without limitation, chemical warfare agent mimics, pesticides and flameretardants, can be treated according to disclosed methods. By way ofexample, disclosed methods can be utilized to remediate a fluid (e.g.,liquid, gaseous, or vaporous) containing one or more organophosphorouschemical warfare agents such as tabun, sarin, or VX; organophosphorouspesticides such as atrazine, aldicarb, alachlor, chloropyrifos,diazinon, and malathion; and/or organophosphorous flame retardants suchas TPP, CDPP, and EHDP. The functional group of the carrier materialscan be bonded either directly or indirectly to the biodegradable carriermaterial and can target one or more contaminants of the fluid. Forinstance, in one embodiment, the functional group can be directly bondedto the back-bone of a non-toxic biodegradable polymer of the carriermaterial. In another embodiment, the functional group can be bonded to abiodegradable polymer via a linker region such as an aliphatic, cyclic,and/or aromatic linker region. When considering copolymers, thefunctional group can be bonded to the copolymer via any suitable segmentof the copolymer. For instance, the functional group can be directly orindirectly bonded via a linker group to the outer PEG shell of aself-organizing PEG copolymer structure. The density of the functionalgroups contained in the carrier materials can vary as desired, with anypreferred amount depending upon the nature of the carrier material aswell as the quantity and type of contaminant to be treated by themethods. For instance the carrier material can include the functionalgroup in an amount of about 0.1 mg or greater of functional group per100 mg of carrier material (e.g., a particle comprising the carriermaterial), about 1 mg or greater of functional group per 100 mg ofcarrier material, about 10 mg or greater of functional group per 100 mgof carrier material, about 20 mg or greater of functional group per 100mg of carrier material, about 40 mg or greater of functional group per100 mg of carrier material, or about 50 mg or greater of functionalgroup per 100 mg of carrier material.

Functional groups can include any material that can target one or morecontaminants in a fluid for either sequestration or modification. Assuch, the preferred functional group(s) in any particular applicationcan depend upon the nature of the carrier material as well as upon thenature of the targeted contaminant(s). Functionality as may beincorporated on the carrier material can include, without limitation,one or more of carboxyl, hydroxyl, amino (primary, secondary, tertiary),amine N-oxides (primary, secondary and tertiary), carbonyl, phosphate,sulfate (e.g., sulfo, sulfonyl, thiol), oxime, halide, aldehyde,ammonium, cyano, imino, nitro, peroxy, pyridyl, etc. Functionality canbe present in a monovalent or multivalent format and can be presented ina monomeric or polymeric form, or a combination thereof. For instance,linear or branched polymers or copolymers carrying one or morefunctional groups that can be the same or different from one another canbe bonded to a carrier material, optionally in conjunction with a linkergroup. In addition, multiple different functional groups can be carriedby a carrier material in the same or different formats.

Functional groups can be components of or derived from synthetic ornatural materials. For instance, functional groups can be derived fromnatural lipid, protein, nucleic acid, or carbohydrate materials and canexhibit desired reactivity toward the targeted compounds. Alternatively,synthetic compounds can be utilized to provide the desired functionalityto the carrier materials. Of course, combinations of naturally derivedand synthetic materials can be utilized to provide a carrier materialwith multiple different functional groups and/or formats for targetingone or multiple targets in a fluid.

Any suitable chemistry can be utilized to bind the desired functionalityto the carrier material. For instance, a carrier material can be formedto include suitable reactive functionality for interaction with thefunctional groups of choice or can be activated following formation andat the time of functionalization. For instance, a polymer of the carriermaterial can be activated by use of carbodiimide chemistry as is knownin the art. Following activation, the desired functional groups can bereacted with the activated sites of the carrier material and therebybonded to the carrier material.

Amine functionality can be utilized to bind one or more contaminants,e.g., aldehydes and/or carboxylic acid contaminants of a fluid. Methodsfor amine-functionalizing the carrier material can, of course, varydepending upon the specific polymer(s) of the carrier material. In oneembodiment carboxylic groups on a carrier material surface can beactivated with a carbodiimide (e.g.,1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC)) andthe activated ester groups of the carrier material can then react with aprimary amine of a compound containing the desired functionality to forman amide bond and bond the functional group-containing polymer to thecarrier material. In one embodiment, the activated carrier material canbe reacted with a relatively low molecular weight amine-containingpolymer such as polyethyleneimine (LMWPEI). LMWPEI is a dendriticpolyamine that can present a number of primary, secondary and tertiaryamines on the surface of the carrier material.

FIG. 4 schematically illustrates one embodiment of a carrier material(PLA-PEG) following functionalization with an amine functional group viaend capping with PEI. FIG. 5A illustrates the expected reactivity of anamine functionalized carrier material with an aldehyde-containingcontaminant via imine formation and FIG. 5B illustrates the expectedreactivity of an amine functionalized carrier material with a carboxylicacid-containing contaminant via acid-base reaction.

While amine functionalized carrier materials can be utilized tosequester a large variety of contaminants including aldehyde, sulfur,and carboxylic acid contaminants, amine functionality may prove lesseffective in neutralizing certain particular contaminants. For instance,the five sulfur-containing compounds associated with renderingoperations are particularly noxious, emitting an overwhelming, putridodor that is detectable even at miniscule concentrations, and certainfunctionalities may be preferable over others in targeting such specificcontaminants. In one embodiment, the carrier material can carry aperoxysulfate functional group capable of oxidatively neutralizingcertain contaminants, such as sulfur-containing contaminants via, e.g.,reaction with a quaternary ammonium peroxysulfate. An ammoniumperoxysulfate decorated carrier material (a schematic illustration ofwhich is provided in FIG. 6) can oxidize the sulfurous VOCs to lessodorous, less-reactive by-products as illustrated as the conversion ofmethanethiol to methyl sulfonic acid illustrated in FIG. 7.

One exemplary method for modifying a carrier material to carry aperoxysulfate functional group can encompass a first step in which apolymer of the carrier material is activated (for instance by use ofcarbodiimide chemistry) followed by reaction with an appropriate linkerthat displays a quaternary ammonium chloride salt. Following, thepolymer can be further processed to form the quaternary ammoniumperoxysulfate-functionalized carrier material via counteranion exchange.By way of example, potassium peroxysulfate (i.e. KHSO₅), the activeoxidant of commercial Oxone®, can be isolated, and the carrier materialincluding quaternary ammonium chloride salt functionality can be treatedwith an aqueous solution of potassium peroxysulfate (i.e. KHSO₅) inorder to exchange the chloride anion on the surface of the carriermaterial with the desired peroxysulfate anion (FIG. 6).

In another embodiment, a PEI-based functionality, such as the LMWPEImaterial described above, can be subjected to bleach oxidation togenerate an amine N-oxide decorated material that is suitable for theoxidative degradation of sulfurous contaminants.

Oxime functional groups can be applied to a carrier material that arecapable of remediating a broad class of organophosphorous (OP) chemicalsincluding chemical warfare agent mimics, pesticides and flame retardantsin both aqueous and gas phase. Reaction between the oxime functionalityand an OP chemical results in chemical transformation and a loss ofdeleterious biological function of the OP compound. Thus, incorporatingthis functional group onto the surface of a carrier material can resultin the development of a robust platform capable of neutralizing thesematerials in the environment via chemical conversion to less harmfulsubstances.

Oxime functionalized carrier materials can be formed by capping apolymer of the carrier material with an amino-oxime polymer via, e.g.,the protocol described above for other functional groups. One exemplarymethod is illustrated in FIG. 8.

An oxime functional group of a carrier material can neutralize OPcontaminants according to a nucleophilic substitution at the phosphorus(V) center (FIG. 9) that results in the sequestration of the materialalong with the deactivation of the OP to ameliorate its biologicaleffect. Briefly, the oxime hydroxyl group attacks the electrophilicphosphonyl (i.e. P═O) of the OP contaminant, generating the intermediatein brackets in FIG. 9. Collapse of that intermediate with displacementof one of the alkoxy substituents results in the covalent harness of theOP contaminant onto the surface of the oxime functionalized carriermaterial with concomitant loss of biological effect.

A carrier material can be functionalized with multiple differentfunctional groups so as to target multiple different contaminantspresent in a single fluid. For instance, a carrier material can befunctionalized so as to carry both amine functional groups and ammoniumperoxysulfate or amine N-oxide functional groups. This hybrid carriermaterial can thus be adequately equipped to capture aldehyde andcarboxylic acid contaminants as well as to oxidize sulfur-containingagents. By such mechanisms, the carrier materials can exhibit greatvariability as well as tunability to target a wide range of contaminantspresent in fluids such as waste streams.

One exemplary process for forming a carrier material that includesmultiple different functional groups can be initiated by activating thecarrier material, as described previously. After formation of theactivated ester (e.g., after EDC treatment), the material can be cappedwith a statistical mixture of two or more unique functional groups bysimply controlling the ratio of the incoming capping groups during thefabrication process. For example, by simultaneously capping the carriermaterial with a mixture of the appropriate amine and quaternary ammoniumsalts, a hybrid functionalized carrier material can be prepared in oneoperation. Subsequent treatment of the quaternary ammonium sites withpotassium peroxysulfate as described above can then produce hybridfunctionalized carrier material equipped with both amines and ammoniumperoxysulfates (FIG. 10) that can target multiple different contaminantsin a mixture that contains, for example, hexanal, hexanoic acid, anddimethyl sulfide.

The functional groups encompassed in the disclosed methods, materials,and systems can be selected so as to interact with a targeted compoundin any suitable fashion. For instance, a functional group can bond witha targeted compound for sequestration and removal and the bond formationcan be covalent, ionic, electrostatic, hydrophilic/hydrophobic, and soforth. Low affinity/high avidity interactions as well as highaffinity/low avidity interaction between a targeted compound and afunctional group are also encompassed herein. Upon bonding, thefunctional group can (though not necessarily) degrade and/or deactivatethe targeted compound so as to render the targeted compound safe fordisposal. In another embodiment, the functional group can interact withthe targeted compound through deactivation and/or degradation of thecompound without bonding between the two. For instance, the functionalgroup can react directly with the targeted compound, e.g., in anoxidation/reduction reaction, so as to render the targeted compound lessnoxious and/or less harmful. Alternatively, the functional group cancatalyze a reaction between the targeted compound and some othercomponent of the waste (e.g., a reactant that can be added to the waste)so as to render the compound safe to remain in the fluid.

Through interaction between the functional groups and the targetedcompound, about 75% or more of the targeted compound, for instance about80% or more, about 85% or more, about 90% or more, about 95% or more orabout 98% or more in some embodiments, can be removed from a fluidand/or modified. Thus, the disclosed methods and systems can be highlyefficient in remediating a fluid.

A system for use in carrying out the disclosed methods can include asystem designed for use in an industrial application in which thecarrier materials can be incorporated into a unit operation of aprocessing plant or a waste treatment system. For instance, a scrubber,filtration system, bag house, etc. for gaseous emissions and/or liquidor solid waste from an industrial operation can incorporate the carriermaterials in a suitable format (e.g., a filtration cartridge, a packedbed reactor, etc.) so as to contact the fluid stream and remove and/ormodify the targeted contaminants.

Systems for utilization of the disclosed materials can also encompassnon-industrial applications. For instance, protective and clean-upsystems are encompassed in which the functionalized carrier materialscan be provided so as to allow for contact with targeted contaminant(s)in a chemical spill or chemical attack scenario. For example, a liquid,solid, aerosol or the like that incorporates the functionalized carriermaterials can be utilized to clean up an area that has been contaminatedwith the targeted contaminants and/or to protect an area or individualfrom contamination with the targeted contaminants. A liquid or aerosolcan be applied to a surface or to a targeted space through spraying,liquid application, or the like, and thus be capable of contact with thetargeted materials. In one embodiment, the carrier materials can beincorporated in a fibrous cleaning wipe, e.g., a cloth orcellulose-based paper wipe that can absorb a liquid, upon which targetedmaterials in the liquid can interact with the functional groups of thecarrier material.

The carrier materials can be incorporated in textiles including, withoutlimitation, upholstery, drapes, rugs, etc. as well as in clothing (e.g.,face masks, protective suiting, etc.) to protect and decontaminate anarea from targeted contaminants and prevent contact between anindividual and targeted contaminants. The carrier materials can beapplied as a coating, for instance, on a fiber or on a formed textileand can serve as a protective coating in the event of contact betweenthe material and the targeted contaminants. By way of example, textilesincluding woven, knitted, and non-woven fibrous goods, e.g., face masks,clothing, upholstery, etc. can include the carrier materials on thesurface and/or within the bulk of the goods (e.g., in the fibersthemselves or in form of micro- or nano-sized particles applied to orwithin the fibers). The functionalized carrier materials can thus serveas a protectant in the event of contact with the targeted compounds(e.g., dangerous chemical agents).

Methods of applying the carrier materials to a structure can include,for example application of a suspension containing the carrier materialsin a particulate form to the structure and subsequent drying (optionallyin conjunction with heating or other energy application) of thestructure to remove the liquid carrier of the suspension. The particlesof the carrier material can be retained on the structure (e.g., a solidsurface, a fiber or formed textile surface) through charge/chargeinteraction, non-covalent bonding, covalent bonding, etc. For instance,a portion of the functional groups added to the carrier material asdescribed above can be utilized to bond the carrier material to thestructure, while a second portion of the functional groups can beretained on the carrier material for interaction with a targetedcontaminant.

One system encompassed herein can provide the functionalized carriermaterials in a packed bed column, such as illustrated in FIG. 11. Thetreatment system can include a flow path for the fluid stream includingan inlet 30 to the column 36 and an outlet 32 from the column 36. Afluid, e.g., a gas, vapor, or liquid fluid, can be directed through thecolumn 36 so as to contact the bed materials 40 contained within thecolumn 36. The bed materials 40 can include the functionalized carriermaterials that, upon contact with the fluid can sequester and/or modifythe targeted contaminants. A column can include standard features suchas diffusers 34 as are known in the art to improve flow and contactbetween the fluid and the bed materials.

According to another system, the carrier materials can be included in afilter or filter cartridge, one embodiment of which is illustrated inFIG. 12. A filter 50 can include the carrier materials, for instance inthe form of fibers utilized in forming a fibrous filter 50. A fibrousfilter 50 can include fibers in a woven or nonwoven mat, as is known. Inaddition, a filter can include particulates adhered to or otherwisecaptured within the fibers of the filter. In such an embodiment, thefunctionalized carrier materials can be in the form of particulates(e.g., nanoparticles and/or microparticles) contained in and/or on afibrous filter 50. In addition, though illustrated as a circular filtercartridge 50, it should be understood that a filter can be in anysuitable shape for location in a flow path and contact between thefunctionalized carrier materials and the targeted contaminants.

In addition, and depending upon the treatment system that incorporatesthe functionalized carrier materials, the carrier materials may becombined with other materials in forming a treatment system component.For instance, fibrous carrier materials can be combined with other fibertypes in formation of a fibrous filter cartridge, protective clothing,face mask, etc.. Similarly, a packed bed column can include additionalmaterials (e.g., other types of particles) in combination with thecarrier materials.

The present disclosure may be better understood with reference to theexamples, set forth below.

EXAMPLE 1

Low molecular weight polyethylene imine capped PLA-PEG nanoparticleswere generated by dissolving PLA-PEG-COON polymer (generated by ringopening polymerization) in acetonitrile (˜5 mg/mL). This acetonitrilesolution was then added dropwise into water to allow for the polymericnanoparticles to form over the course of about 1.5 hours. The individualpolymer strands self-assemble into nanoparticles byhydrophobic-hydrophobic interactions between the PLA polymer chain suchthat the hydrophilic PEG outer layer was projected into the aqueoussolvent. After the 1.5 h incubation, the nanoparticles were washed byultracentrifuge filtration to remove residual solvents.

The nanoparticles were then re-suspended in phosphate buffered saline(PBS) (pH 7.4) and then incubated in a 10X molar excess of1-ethyl-3-[3-dimethylaminopropyl] carbodiimide (EDC) in PBS (pH 7.4) togenerate the activated ester. The amine cap (i.e., LMWPEI) was thenadded as a 10X excess to the activated ester-containing nanoparticlesand incubated for six hours in order to load the amine cap via amideformation. The amine-capped PLA-PEG nanoparticles were then washed threetimes with distilled water using ultracentrifugation and dried using afreeze dryer.

After preparation, the nanoparticles were characterized by 1H nuclearmagnetic resonance (NMR) spectroscopy, infrared (IR) spectroscopy, andthermogravimetric analysis (TGA). The presence of the aminefunctionality on the surface of the NPs was further verified by zetapotential measurements. Nanoparticle size was judged by zetasizermeasurements to be about 100 nanometers.

EXAMPLE 2

The PLA-PEG-LMWPEI nanoparticles described above were utilized tocapture gaseous samples of target VOCs associated with renderingoperations. Briefly, 10 mg of a freshly prepared sample ofPLA-PEG-LMWPEI nanoparticles was suspended on a tissue paper barrierabove a 14 aliquot of analyte in a GC vial (FIG. 13). Thus, thenanoparticles were allowed to interact with the vapor portion of theanalyte sample for 30 minutes. Headspace analysis was conducted by gaschromatography (FID detection). Analyte samples were treated withPLA-PEG-LMWPEI nanoparticles minutes and untreated tissue paper wasutilized as control. Samples were treated for 30 minutes. Singleanalytes as well as mixtures of two different analytes were examined.Untreated control samples demonstrated no reduction in gas-phase analyteconcentration. The table below provides results for several differentanalytes (data collected in sextuplicate).

Analyte Percent reduction Hexanal 97 ± 2 Hexanoic acid 86 ± 6Butyraldehyde 86 ± 4 Butyric acid 86 ± 6 2-methylbutanal 81 ± 43-methylbutanoic acid 76 ± 6 Octanal  77 ± 12 Nonene 14 ± 2Hexanal/Hexanoic Acid 90 ± 7/69 ± 6 Hexanal/Octanal  87 ± 6/52 ± 18Hexanal/Nonene 63 ± 35/46 ± 29 Hexanoic Acid/Nonene 71 ± 3/10 ± 2

Three different nanoparticles were examined for hexanal reduction.Notably, the reduction in hexanal concentration was only observed withthe amine-functionalized nanoparticles (FIG. 14). “Average Area” on FIG.14 refers to the average peak area under the curve for an analytechromatogram peak over six sequential runs. The percent reduction oftarget analyte was determined by calculating the reduction in peak arearelative to calibrated, untreated control samples. Treatment of hexanalwith nanoparticles end-capped with carboxylic acids (—COON) or methylesters (—COOCH₃) did not appreciably reduce the concentration of hexanal(FIG. 14) underscoring the necessity of a functional group cap withcompatible reactivity, and further demonstrating the uniquetarget-specific selectivity of the disclosed method. These data alsoindicate that the amine-capped nanoparticles likely capture hexanal viacovalent reaction in lieu of non-specific electrostatic adsorption.These results clearly indicate that the PLA-PEG-LMWPE I nanoparticlesare equipped with appropriate functionality to capture aldehyde VOCpollutants associated with rendering emissions.

EXAMPLE 3

The potential toxicity of the nanoparticle formulations was examined. Asan initial evaluation, the base nanoparticle formulation (PEG-PLA-COON)was examined for acute toxicity in a Daphnid (water flea) aquaticinvertebrate model. Briefly, the nanoparticles were tested for toxicityusing a standard Daphnia magna acute toxicity test, according to US-EPAprotocol. The nanoparticles were tested at 7 concentrations ranging from1 to 5000 ppm, plus appropriate controls without nanoparticles. The testorganisms were cultured in standard D. magna culture media, and fed amixture of Selenastrum capricornutum and fish food on a daily basis.Daphnid cultures and test beakers were maintained in a climatecontrolled room at 20 ° C. and 16/8 h light/dark cycles. On the day ofthe toxicity test, neonate daphnids (less than 24 h of age) werecollected from the culture, and introduced into the test beakers. Eachbeaker contained 40 mL of media with the nanoparticles dissolved, and 5neonates per beaker. Each nanoparticle concentration was tested in 4replicate beakers. Neonates were exposed for 48 h and were not fedduring the exposure. After the exposure period, test animals werechecked for mortality. The results showed no significant mortality inany of the tested nanoparticle concentrations.

It will be appreciated that the foregoing examples, given for purposesof illustration, are not to be construed as limiting the scope of thisdisclosure. Although only a few exemplary embodiments of the disclosedsubject matter have been described in detail above, those skilled in theart will readily appreciate that many modifications are possible in theexemplary embodiments without materially departing from the novelteachings and advantages of this disclosure. Accordingly, all suchmodifications are intended to be included within the scope of thisdisclosure. Further, it is recognized that many embodiments may beconceived that do not achieve all of the advantages of some embodiments,yet the absence of a particular advantage shall not be construed tonecessarily mean that such an embodiment is outside the scope of thepresent disclosure.

What is claimed is:
 1. A method for remediating a fluid comprisingcontacting a fluid with a biodegradable and non-toxic polymeric carriermaterial, the fluid comprising a contaminant, the polymeric carriermaterial comprising a biodegradable polymer and a functional group, thefunctional group interacting with the contaminant upon the contact tosequester and/or to modify the contaminant.
 2. The method of claim 1,wherein the fluid comprises a gas, a vapor, a liquid, or a combinationthereof.
 3. The method of claim 1, wherein the contaminant comprises avolatile organic compound, a hazardous material, a pharmaceutical, acomponent of a personal care product, a perchlorate, or anendocrine-disrupting compound.
 4. The method of claim 1, wherein theinteraction comprises binding the functional group with the contaminant.5. The method of claim 4, wherein the functional group binds about 75%or more of the contaminant contained in the fluid.
 6. The method ofclaim 1, wherein the functional group oxidizes the contaminant.
 7. Themethod of claim 1, wherein the fluid is a flowing waste stream.
 8. Themethod of claim 1, wherein the polymeric carrier material is a componentof a particle, a fiber, a sheet, or a film.
 9. The method of claim 1,wherein the biodegradable polymer comprises a natural polymer.
 10. Themethod of claim 9, wherein the biodegradable polymer comprisespoly(lactic acid).
 11. The method of claim 10 wherein the biodegradablepolymer comprises a poly(lactic acid)-polyethylene glycol blockcopolymer.
 12. The method of claim 1, wherein the functional groupcomprises amino, amine N-oxide, sulfate, oxime, hydroxyl, carboxyl,carbonyl, phosphate, halide, aldehyde, ammonium, cyano, imino, nitro,peroxy, or pyridyl functionality or a combination of functional groups.13. The method of claim 1, wherein the functional group is bonded to thebiodegradable polymer by a linker.
 14. The method of claim 1, the fluidcomprising multiple contaminants, wherein the polymeric carrier materialinteracts with two or more of the multiple contaminants.
 15. Acontaminant remediation system comprising: a fluid flow path; and apolymeric carrier material located within the fluid flow path, thepolymeric carrier material including a functional group that is reactivewith a contaminant.
 16. The contaminant remediation system of claim 15,the system comprising a packed bed column, the polymeric carriermaterial being located within the packed bed column.
 17. The contaminantremediation system of claim 15, the system comprising a filter, thefilter comprising the polymeric carrier material.
 18. The contaminantremediation system of claim 15, the system including fibers orparticles, the fibers or particles comprising the polymeric carriermaterial.
 19. The contaminant remediation system of claim 15, whereinthe contaminant remediation system is a component of a textile.
 20. Thecontaminant remediation system of claim 15, wherein the contaminantremediation system is a component of an industrial waste processingsystem.